A049697 a(n)=T(n,n+1), array T as in A049695.

1, 3, 6, 10, 16, 22, 30, 40, 50, 60, 74, 88, 104, 122, 136, 152, 176, 198, 222, 248, 268, 290, 322, 352, 380, 412, 442, 472, 512, 548, 586, 632, 668, 704, 744, 780, 828, 882, 924, 964, 1020, 1072, 1126

Offset

0,2

Links

Table of n, a(n) for n=0..42.

Formula

a(n-1)=sum_{k=1...n}mu(k)floor(n/k)ceiling(n/k); a(n) is asymptotic to (6/Pi^2)*n^2 - Benoit Cloitre, Jun 27 2005

Prog

(PARI) a(n)=sum(k=1, n++, n\k*moebius(k)*ceil(n/k)) \\ Charles R Greathouse IV, Mar 02 2012

Crossrefs

Cf. A018805.

Sequence in context: A327141 A283503 A294481 * A111712 A293407 A194144

Adjacent sequences: A049694 A049695 A049696 * A049698 A049699 A049700

Keyword

nonn

Author

Clark Kimberling

Status

approved